1. Field of the invention
The present invention relates to folding machines for rotary printing machines and more particularly to a composite type folding machine which discharges separately two kinds of sheets of paper, cut from paper on which two kinds of patterns are printed alternately and successively, in the form of a folded sheet or in the form of folded collected sheets for each pattern.
2. Description of the related art
FIG. 9 schematically illustrates a conventional general folding machine.
In FIG. 9, printed paper 102 on which two kinds of patterns A and B are printed alternately and successively is folded along a longitudinal line by a former 101. The folded paper 102 is inserted between a cutting cylinder 103 and a pin cylinder 104 and cut into pieces having a pattern A or B width by two cutting blades 103a provided in the cutting cylinder 103 so that the cut sheet 102A or 102B has a pattern A or B, respectively. The cut sheets 102A and 102B are sequentially supported one by one by two pins 104a provided on the pin cylinder 104 and delivered sequentially to three pins 105b provided on a thrusting cylinder 105.
The thrusting cylinder 105 has three folding blades each provided between two adjacent pins 105b. Provided adjacent to the thrusting cylinder 105 is a gripping cylinder 106 which has six gripping jaws 106a which alternately grip a cut sheet 102A or 102B.
A pin 105b which supports the cut sheet 102A or 102B at a timing in which the folding blade 105a of the thrusting cylinder 105 and the gripping jaw 106a of the gripping cylinder 106 coincide is retracted from that sheet and this sheet 102a or 102B is then delivered to the gripping jaw 106a. By this operation, the cut sheet 102A or 102B is folded transversely in two. The folded sheet is then gripped by the gripping jaw 106a, distributed sequentially to an upper gripping cylinder 107 or a lower pawl cylinder 108 and discharged.
The operation of the pin 105b of the thrusting cylinder 105 or the gripping pawl 106a of the gripping cylinder 106 in the folding machine of FIG. 9 is performed by a rotary cam (not shown) provided on each of the thrusting and griping cylinders 105 and 106.
When the cut sheets 102A and 102B are collected or superposed and folded by the conventional folding machine shown in FIG. 9, there are the following problems:
A rotary cam (not shown) provided in the gripping cylinder 106 comprises cam portions each capable of moving reciprocality toward its radial direction, so that it is required to shift respective cam portions as to be desired. And the even number of the gripping jaws 106a of the gripping cylinder 106 are required to be controlled alternately so as not to operate. Therefore, the switching operation between the discharge of the folded sheet of the pattern A or B in separate and the discharge of folded collected sheets of the different patterns A and B is troublesome.
Since the rotary cam is provided not only in the gripping cylinder 106 but also in the thrusting cylinder 105 in the conventional folding machine, harsh noise or the like will occur due to vibrations on a drive system for the rotary cam to project and retract the pin 105b but also the rotation of the thrusting cylinder 105 is not performed smoothly.
When one plate having different patterns A and B in both is to be attached onto a plate cylinder, the operator can wrongly attach the plate at unfavorable reverse position on the plate cylinder. In that case, the position where the folded sheet is to be discharged from the griping cylinder 106 toward the upper gripping cylinder 107 or toward the lower gripping cylinder 108 must be changed on the opposite side of the gripping cylinder 106. To this end, the actuating and non-actuating gripping jaws 106a must be rearranged reversely, which is a troublesome adjustment.
Published Unexamined Japanese Patent Application Sho 62-70172 discloses a folding machine which is intended to solve the troublesome selection between folded collected cut sheets and folded separate or non-collected cut sheets.
This folding machine includes a cutting cylinder having cutting blades, a thrusting cylinder disposed adjacent to the cutting cylinder and having retractable pins and folding blades disposed alternately at intervals along the periphery of the thrusting cylinder, and gripping cylinders disposed close to the thrusting cylinder and having gripping mechanisms (gripping jaws). It hooks printed paper at one end with a pin of the thrusting cylinder to wind the paper around the thrusting cylinder, cuts the paper with a cutting blade and folds the cut sheet with a folding blade of the thrusting cylinder into a gripping mechanism of the gripping cylinder. In the folding machine, the diameter of the thrusting cylinder is selected so as to be one and a half times that of the cutting cylinder, the number of pins and the number of folding blades of the thrusting cylinder are three each, two gripping cylinders are disposed at angular intervals of 120 degrees at which the folding blades are disposed. Two fixed cams, two rotary cams and one manually rotatable cam are provided at the side of the thrusting cylinder to project and retract pins and folding of the thrusting cylinder. These fixed and rotary cams blades can operate the folding blades located on the gripping cylinder sides each time the thrusting cylinder rotates through 2/3 of a complete rotation to deliver the cut sheets into the gripping mechanism while folding the cut sheets and simultaneously retracting the two pins from the associated cut sheets folded by the folding blade. The manually rotatable cam is constructed such that it operates the two folding blades and the two pins of the thrusting cylinder to bring about a state in which a non-collected or separate folded sheet is obtained or a state in which collected or superposed folded sheets are obtained by actuating one of the two folding blades and one of the pins.
However, the folding machine of the Publication requires one fixed cam, one rotary cam and one manually rotatable cam; namely, three cams in total to operate the pins, and hence the mechanism is complicated.
In this folding machine, the two gripping cylinders are disposed at an angular intervals equal to that at which the folding blades are disposed, so that the folded sheets are delivered from the thrusting cylinder to the respective gripping cylinders at the same timing (interval). Therefore, the single fixed cam and the single rotary cam cannot select only any one of the two gripping cylinders and discharge the sheets to that cylinder. Therefore, a fixed cam is inevitably required to be provided in addition to the first-mentioned fixed cam and the rotary cam in order to select any one of the two gripping cylinders.
Published Unexamined Japanese Patent Application Sho 62-70173 discloses an invention described using the same embodiment as that in the Publication Sho 62-70172. Claims of the Application Sho 62-70173 discloses a folding machine which discharges non-collected or separate folded sheets simultaneously into two directions and which omits a description concerning the manually rotatable cam. Therefore, collected folded sheets cannot be produced according to the arrangement disclosed.
It is an object of the present invention to provide a simple-structured composite type folding machine which freely selects one of collected folded sheets and separate folded sheets without requiring any complicated adjusting operations.